Intensive Care

The electrical properties of the skin, also known as electrodermal activity (EDA), are considered as an indirect measure of autonomous nervous system. Along with that, the effects of noise-induced stress in intensive care units, is well explored. This study explores the noise-induced acute electrodermal activity changes in adult critical care patients and to compare these changes with cardiovascular effects of the same stress (noise) stimulus. Skin conductance variability, noise level, selected hemodynamic and respiratory parameters were monitored during 4 hour routine daytime intensive care nursing and treatment in an adult Intensive Care Unit. Average ambient noise levels during the time window (4 min) before the stimulation were 54.33(2.65) dB for Group A and 55.65(3.31) dB, while the noise stimulation was on average for Group A 70.8 (1.98) dB, and for Group B: 71.31(3.31) dB. EDA changes to noise stimulus were more distinct than hemodynamic and respiratory parameters. Yet, a weak relation was found between all EDA parameters and the particular noise level changes. Noise-induce stress causes more distinct EDA changes when measured immediately post stimulus. In addition, sedation level seems to affect the intensity of these changes. However, further studies are needed in to order to reach a definite conclusion. Continue reading →

Patient care in Intensive Care Units is characterized by high demanding tasks, which leads in daily high workload. The aim of the study is to evaluate the effect of patient’s sedation level to workload for the certain task. It also examines whether workload lowers over time, as an effect of the experience gained by the repetition of the task. NASA- TLX tool was used as workload assessments method during a complex monitoring task in an adult Intensive Care Unit environment. The latter included monitoring and recording of skin conductance variability, noise level, hemodynamic and respiratory parameters were monitored during 4 hour routine in two groups of patients. The group was defined by the sedation level (Ramsay sedation score); otherwise no major differences were spotted in their characteristics. Both raw and weighted data of the NASA-TLX tool were included in the analysis, which was performed with MS Excel 2007 (Microsoft Co, USA) and Rstudio® IDE v.0.99.903 (Rstudio Inc, Boston, MA, USA). Patients’ sedation level did not affect NASA-TLX measured workload. The former was valid both for raw values and weighted data of the subscales of the NASA-TLX tool. In the second part of the analysis where the raw values were treated as time series data, it was shown that some subscales (Ment, Phys) had a tendency towards lower values, others (e.g. Temp, Ef) had a relative stability and others (Per) increased over time. The total workload (OW) did not seem to lower over time. While the patient’s sedation level does not affect workload of the specific task, several subscales of the NASA-TLX index do reveal a tendency over time; a fact that may be used as learning curve/ experience assessment for a given task. However, further studies are needed in order to define its future utility.